Noise suppression systems

Patent metadata

Field	Value
Publication number	US-9752494-B2
Application number	US-201314045657-A
Country	US
Kind code	B2
Filing date	Oct 3, 2013
Priority date	Mar 15, 2013
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

An apparatus or system includes a component that generates or transfers noise having a frequency within a noise frequency range. The component may include a boundary. The apparatus or system may be an engine in some examples. The engine may additionally include a micro-perforated sheet positioned a distance from the boundary. The micro-perforated sheet may include a plurality of micro-perforated holes, and may be configured to absorb sound within an absorption frequency range based on parameters of the micro-perforated sheet. The parameters may include the distance from the boundary and dimensions of the micro-perforated holes, and may be set such that the absorption frequency range overlaps the noise frequency range.

First claim

What is claimed is:

1. An engine comprising:
a cylinder that generates or transfers noise having a frequency within a noise frequency range, the cylinder comprising a side surface;
a plurality of cooling fins extending radially from the side surface of the cylinder;
micro-perforated cylinder wrap comprising a micro-perforated sheet positioned a first lateral distance from the side surface of the cylinder, the micro-perforated sheet positioned proximate to ends of the cooling fins and comprising a plurality of micro-perforated holes, the micro-perforated sheet configured to absorb sound within an absorption frequency range based on parameters of the micro-perforated sheet;
wherein the parameters include the distance from a boundary and dimensions of the micro-perforated holes, and wherein the parameters are set such that the absorption frequency range overlaps the noise frequency range;
wherein an inner surface of the micro-perforated sheet facing the cylinder is free of acoustic insulation; and
wherein the micro-perforated cylinder wrap has a shape that conforms to a shape of the cylinder.

2. The engine of claim 1 , wherein the parameters are set such that the absorption frequency range overlaps a portion of the noise frequency range consisting of sound between 300-1500 Hz for tonal noise and sound between 800-3000 Hz for flow noise.

3. The engine of claim 1 , wherein the micro-perforated cylinder wrap has a curved shape that conforms to the shape of the cylinder.

4. The engine of claim 1 , wherein the micro-perforated cylinder wrap has a flat shape.

5. The engine of claim 1 , wherein the micro-perforated cylinder wrap is formed of a metal sheet material.

6. An engine comprising:
a cylinder that generates or transfers noise having a frequency within a noise frequency range, the cylinder comprising a side surface;
a plurality of cooling fins extending radially from the side surface of the cylinder;
a micro-perforated cylinder wrap comprising a micro-perforated sheet positioned a first distance from the side surface of the cylinder, the micro-perforated sheet positioned proximate to ends of the cooling fins and comprising a plurality of micro-perforated holes, the micro-perforated sheet configured to absorb sound within an absorption frequency range based on parameters of the micro-perforated sheet; and
a baffle wall positioned at a second distance from the cylinder wrap and collectively forming a micro-perforated panel with the micro-perforated sheet, the second distance defining a cavity creating an air space between the baffle wall and the micro-perforated sheet;
wherein the parameters include the distance from a boundary and dimensions of the micro-perforated holes, and wherein the parameters are set such that the absorption frequency range overlaps the noise frequency range.

7. The engine of claim 6 , wherein the second distance is selected such that the baffle wall is positioned at a distance of lowest wave pressure from the micro-perforated sheet of the cylinder wrap.

8. The engine of claim 6 , wherein the second distance equals the first distance.

9. An engine comprising:
a cylinder that generates or transfers noise having a frequency within a noise frequency range, the cylinder comprising a side surface;
a plurality of cooling fins extending radially from the side surface of the cylinder;
a micro-perforated cylinder wrap comprising a micro-perforated sheet positioned a first distance from the side surface of the cylinder, the micro-perforated sheet positioned proximate to ends of the cooling fins and comprising a plurality of micro-perforated holes, the micro-perforated sheet configured to absorb sound within an absorption frequency range based on parameters of the micro-perforated sheet; and
a baffle wall positioned at a second distance from the cylinder wrap and collectively forming a micro-perforated panel with the micro-perforated sheet, the second distance defining a cavity creating an air space between the baffle wall and the micro-perforated sheet;
wherein the parameters include the distance from a boundary and dimensions of the micro-perforated holes, and wherein the parameters are set such that the absorption frequency range overlaps the noise frequency range;
wherein the second distance is selected so that the cavity absorbs noise within the noise frequency range of the noise generated by the cylinder.

Assignees

• Kohler Co

Inventors

• Le Roy Tyler W
• Baumann Todd A
• Snyder Dale D
• Adams Amy

Classifications

• F04D29/665

  by means of resonance chambers or interference · CPC title

• F04D29/4213

  suction ports · CPC title

• F01P11/12 Primary

  Filtering, cooling, or silencing cooling-air · CPC title

• F04D29/582 Primary

  specially adapted for elastic fluid pumps · CPC title

• F04D29/424

  Double entry casings · CPC title